This invention relates generally to the treatment of superficial pain syndromes and, in particular, to improved uses of capsaicin to treat these conditions. Over the past 5 years topical capsaicin has emerged as the treatment of choice for superficial pain syndromes such as postherpetic neuralgia. See, for example, U.S. Pat. No. 4,536,404 entitled "Method and Composition for Treating Post-Herpetic Neuralgia", issued Aug. 20, 1985 to the inventor named herein. However, from 10% to 30% of patients treated with topical capsaicin experience moderate to severe local reactions, principally stinging or burning of the skin on initial applications. After a period of use, these reactions seem to fade. However, such burning may cause some of these patients to discontinue capsaicin use before they can experience pain relief from the treatment.
It has been discovered that incorporating topical anesthetics such as lidocaine (Entry 5310, p. 786, Merck Index, Tenth Edition 1983) and benzocaine (ethyl aminobenzoate, Entry 3710, p. 546, Merck Index, Tenth Edition 1983; into formulations containing capsaicin and then applying such formulations for the initial period of treatment can reduce or even eliminate the painful burning from the application of capsaicin, allowing the patient to continue therapy thereafter without requiring the use of anesthetics.